The U.S. Justice Department and multiple states are discussing also suing Moody's Corp. for defrauding investors, according to people familiar with the matter, but any such move will likely wait until a similar lawsuit against rival Standard and Poor's is tested in the courts.

Inquiries into Moody's are in the early stages, largely because state and federal authorities have dedicated more resources to the S&P lawsuit, said the sources, who were not authorized to speak publicly about enforcement discussions.